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Reinstall Catalina On Mac

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Recently switched to macOS 11 Big Sur? This means you’re in for some huge enhancements and a completely redesigned look. It's fair to say Big Sur is not a perfect fit for everyone, though. Can you go back to previous macOS if that's the case? Sure. In this article, we describe how to downgrade from macOS 11 and continue using your previous macOS without any data loss.

Easy & simple way to reinstall Mac if you are thinking about selling your computer or simply need to install a fresh copy macOS Catalina follow the tutorial. Reinstall your computer’s original version of macOS (including available updates): Press and hold Shift-Option-Command-R. Reinstall the version of macOS stored on your computer’s built-in recovery volume: Press and hold Command-R. In the Recovery app window, select Reinstall macOS Big Sur, then click Continue. Follow the onscreen instructions.

Toolkit for safe macOS downgrade

Easily switch between macOS versions with Setapp. Get access to the apps that will keep your Mac invincible and your data protected.

Before you make a decision to uninstall Big Sur, check out some common macOS 11 problems and fixes. Maybe, the problem that is hampering your flow is on the list — and you can easily solve it. Also, if your Mac runs macOS Big Sur beta, you should know the public version available starting November 12 fixes most of the problems.

If you go like 'All right, thanks, just tell me how do I uninstall Big Sur from my Mac' — fair enough. The good news is it's easy to roll back macOS update. Follow the guide below.

How to downgrade from Big Sur step by step

Just to clarify the process a little bit, a downgrade from Big Sur covers five important steps — from backing up all the files you've acquired since upgrading, to restoring those on macOS Catalina. There are a few tools you'll need to use to downgrade safely: Primarily, a backup utility (Apple's native Time Machine or a more advanced third-party app like Get Backup Pro) and CleanMyMac X for keeping things tidy. Now when you're all set, let's get into it.

Best backup app for Mac

Before you roll back to the old macOS, create a secure backup of all your data with Get Backup Pro. So that there’s nothing to lose.

1. Backup your data (pretty please)

Even if you've just recently upgraded and haven’t managed to accumulate lots of data on macOS Big Sur, don’t skip this step. Downgrading means you erase everything from your hard drive. So whatever you’ve been working on since installing macOS 11 will be gone. Make sure you avoid the trouble and create a quick backup. You can do this with Time Machine, but we recommend Get Backup Pro for creating a bootable backup. This will give you an exact copy of your drive, with all saved settings — so that you can pick up where you left off.

Here’s how to back up data before you uninstall Big Sur:

  1. Open Get Backup Pro from Setapp

  2. Hit the plus button at the bottom to create a new backup

  3. Name your backup project

  4. Pick a backup destination and customize settings if necessary

  5. Choose files, folders, and apps data you want to add to the backup

  6. Hit Start.

It’s a good idea to use CleanMyMac X for a system cleanup before you create a backup. This way, you’ll avoid backing up unneeded files and duplicates, and therefore run a smooth and quick backup process. Plus, the app is generally a good tool to keep at your fingertips to remove any clutter. Believe me, your Mac has a lot of it. Here’s how CleanMyMac X works:

  1. Open the app and hit Scan

  2. Wait for CleanMyMac X to finish the scanning process

  3. Hit Run if you want to remove all the junk, or Review if you want to select the files that should be deleted manually

  4. That’s it! You’re all set for a clean backup.

2. Install macOS Catalina on a bootable drive

It might seem a bit counterintuitive, but you have to install macOS Catalina on an external drive before you erase Big Sur. This requires some Terminal work, which we’ll guide you through in a minute. Before that, make sure your Mac can boot from external media.

Allow booting from external media on new Macs

If you own a MacBook Air, MacBook Pro, or Mac mini with the T2 security chip (2018 models and newer), you might experience problems with booting files. To avoid this, you should allow booting from external media before you run downgrade to Catalina:

  1. Restart your computer and boot in Recovery Mode (hold down Command + R once the Apple logo appears)

  2. Access Utilities > Startup Security Utility

  3. Enter your firmware password (note that this is the password you used to enable Startup Security Utility and it’s different from your admin and Apple ID credentials)

  4. In External Boot, check the box next to “Allow booting from external media.”

Once you’re all set, it’s time to get Catalina back. First, download macOS Catalina from the Mac App Store, the usual way. While installers of the latest macOS versions are available only before the official release of the new one, you should do this as early as possible.

Then, install macOS Catalina on an external drive. Start with formatting the drive (you can skip this step if you have a formatted drive):

  1. Get an external drive with minimum 12GB of free space

  2. Connect it to your Mac via USB

  3. Open Finder > Applications

  4. Navigate to Utilities > Disk Utility

  5. Click Erase next to your drive (make sure you name it if you have more than one)

  6. Select APFS or macOS Extended format > Erase.

Install macOS Catalina on a formatted drive:

  1. Open Finder > Applications

  2. Launch Terminal from Utilities

  3. Type the following command

sudo /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia--volume /Volumes/MyVolume

Note that “MyVolume” in the command above is the name of your drive, so you should change it accordingly.

  1. Click Enter/Return

  2. Confirm your action by entering the admin password > Y

  3. Click Return

  4. Once Terminal says “Done,” you can quit it and eject the hard drive.

3. Remove macOS 11 from hard drive

Catalina

Now is the time for goodbye. Here’s how to downgrade from Big Sur to Catalina by removing macOS 11 from your hard drive:

  1. Click on the Apple logo and select Restart from the menu

  2. Hold down Command + R to reboot in Recovery mode

  3. Open Disk Utility > Continue

  4. Select your Startup Disk > Erase

  5. Select APFS or macOS Extended format and confirm your action.

4. Reinstall macOS Catalina on your Mac

Next thing, run a downgrade to Catalina by reinstalling it on Mac:

  1. Make sure your Mac is connected to the internet

  2. Connect your bootable external drive

  3. Click on the Apple logo and select Restart from the menu

  4. While your Mac restarts, hold down Option

  5. Once the list of startup disk options appears, select the bootable drive with macOS Catalina installer

  6. Hit Continue, agree to the licensing terms, and wait for macOS Catalina to reinstall.

5. Restore data from backup

The last step is to bring back all the data you’ve compiled since upgrading to Big Sur. Again, a backup is essential since it will help restore both your files and saved settings. You can restore everything with the same tool you’ve used previously to create a backup.

Here’s how to restore a Time Machine backup:

  1. With your Mac connected to the internet, restart the system

  2. Hold down Command + R to enter Recovery

  3. Access Utilities > Restore from Time Machine Backup > Continue

  4. Select the backup source > Continue

  5. Select your backup > Continue

  6. After Time Machine restores data from the backup, your Mac will reboot.

If you used Get Backup Pro for your backup, restoring data is even easier. All you have to do is launch the app, select your backup from the list, and hit Restore. Select a custom location for your files and once again click on the Restore button. That’s it. All your data and settings will be back on macOS Catalina in a minute.

That’s about it. Whenever you’re wondering how to go back to previous macOS, you can use the guide described above. All the instructions are pretty universal, except you should adjust the Terminal command when installing old macOS on a bootable drive.

In case your Mac is slowing down or else behaving strangely after the downgrade, we recommend to get iStat Menus for advanced system performance monitoring. This app will help you understand the source of the problem — whether it’s login items, network problems, or disk activity — and fix them accordingly.

Reinstall Catalina On Macbook Pro

Catalina

iStat Menus is available on Setapp, along with the useful utilities like CleanMyMac X and Get Backup Pro. So you can use it all from one place for 7 days free. Hopefully, this toolkit will help you with how to downgrade macOS Big Sur, as well as keep your Mac in perfect shape, anytime.

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I’ve been driving myself insane over the past few weeks months shopping for a new computer. So many options, so many new features. (Such high prices!)

During this search, I decided to take advantage of Apple’s 14-day trial period and test out a few of Apple’s newest MacBook Pros. Both of them were seriously impressive machines. If it was my first Apple computer I’d probably go ahead and buy them. But, they weren’t my first Apple machines. These computers were running Catalina which I was unfamiliar with. Due to changes in the operating system, an insignificant number of fonts, files, and several programs I use a few times a year were not recognized and couldn’t be opened. This was too much for me to deal with in those 14-days, so I decided to return the computers and keep exploring my options.
Before returning them to Apple, I needed to wipe the drive clean. Apple has 3 articles outlined on their site on how to do this.
What to do before you sell, give away, or trade in your Mac
How to erase a disk for Mac
About macOS Recovery
Maybe because the instructions are split across 3 different web pages, I got confused and missed a step, wasted time, and finally ended up calling into their help desk.

So for my own reference, let me talk you through my experience. If you need to do this for a computer running Catalina, maybe my experience will help fill in some blanks.

Quick Add: I tested 2 other computers running Mojave and Sierra, since originally writing these steps. I followed these steps each time. I made a few updates where relevant based on those experiences, including a computer with a 3rd-party SSD installed.

Primary Steps to Wiping a Macintosh Hard Drive Running Catalina

These are the main steps to wiping your data from the computer. First you’ll be removing your Apple ID, then wiping security settings like your fingerprint ID. Then you’ll erase the drive and reinstall macOS. The entire process takes 1-2 hours.

1. Create a backup. In my case, since I had transferred files from a backup, I didn’t need this. But if this is your first computer, you should.
2. Sign out of iCloud. This worked exactly as Apple describes it for Catalina. iCloud is available in System Preferences. I think it did require my Apple ID or my computer’s administrator password. (Actually for one of these computers, I didn’t fully log out. Thankfully, you can log into iCloud via another computer and log out that way.)

Update: In 2 cases, I had devices that remained connect to my AppleID despite signing out of iCloud out on the computer. Neither of these devices were running Catalina. I recommend that after you sign out of your computer, visit your Apple ID and check that the device has been removed from your account. You may also need to check your other devices, too (iPhone, iPad, etc). Disappointing this isn’t part of Apple’s instructions.

3. Sign out of iMessage. I didn’t use iMessage, so I couldn’t sign out. (Or maybe that’s why I was still logged in!) In fact, this step was the first time I’d even opened iMessage, which I don’t use. I did see messages from years ago that got transferred over from my original backup file.
4. Reset NVRAM. This is supposed to delete security settings, like perhaps the fingerprint authorization if you’re using a laptop with the TouchBar.

  • In order to reset NVRAM, you shut down your computer. When you restart, immediately press and hold Option+Command+P+R for about 20 seconds. There’s no real indication anything is happening. I ended up trying this about 3 times before deciding I was done.
  • What should happen is you shut down, press Power, the Apple logo appears. Press and hold the keys, the Apple logo goes away. When you let go after 20-30 seconds, it comes back.
  • Note: I tried this on a 2019 iMac running Mojave. The Apple logo went away, then came back on its own after a few seconds. On a MacBook Pro running Sierra, I heard the restart repeating about 3 times until I let go.

5. Unpair Bluetooth devices(as needed). No pairs for me.

6. Erase your hard drive and reinstall macOS. This is the hard part. Apple actually explains this in more detail on another page, which might be why it’s a little confusing.

This section was tricky for me because I mistakenly assumed the options for erasing a drive on Catalina were the same as my other computer running El Capitan. No! Well, I ended up consulting a few sources because none were absolutely clear.

Here are the 13 steps for fully erasing the hard drive.

13 Steps to Erase the Hard Drive (or Step 7 continued):

7.1 Shut down the computer.

7.2 Restart while pressing and holding Command + R. Don’t let go until you see the MacOS Utilities menu. (Actually, you can let go once you see the Apple logo. A language menu will show first.) This boots the computer in Disk Recovery. There will be a few options in Disk Recovery:

  • Restore from a Time Machine backup
  • Disk Utility [This is what you want]
  • Reinstall MacOS
  • Get help online (opens in a Safari, only)

7.3 Select Disk Utility. Once you get in here, you’ll see the same Disk Utility as if you’d searched in System Preferences.

7.4 Select View All. This is a critical step!! The drives you need for Catalina (as well as Mojave) are hidden by default. Make sure you complete this step by selecting View All to view all hidden drives.

7.5 Select your drive. Once you’re viewing the full list of drives, after selecting View All, you should select the very first one at the top of the list. You may have given it a new name, but this is your main drive.

7.6 Select Erase to view erase options. After selecting your drive, the options at the top of the window should include Erase, which should not be inactive at this point. Select Erase to open the menu options for your drive (see image).

  • Regarding drive naming options: When I managed to complete this correctly, I was on the phone with an Apple support technician. She told me I did NOT need to name the drive — e.g., ‘Untitled’ was fine. So although the image above clearly shows someone naming the drive Apple SSD, I did not. However…attempting this on that iMac with a 3rd-party SSD installed, it didn’t like ‘Untitled’ so I used the name of the 3rd-party drive.
  • The drive format: Apple’s instructions essentially say that whatever pops up as the default option is fine to stick with.

7.7 Erase the drive. Once all options have been made, click Erase. Deleting only takes a few moments. You’ll get a confirmation that the erase was successful.

7.8 Quit Disk Utility. After the drive is erased, you’re done. Close out of Disk Utility. You’ll return to the previous screen, Disk Recovery.

7.9 Back in Disk Recovery, select Reinstall MacOS.

7.10 Select ‘Untitled’ during the reinstallation process. After 7.9, the installation process will ask where to install MacOS. Choose the drive that was erased. It will be named ‘Untitled’ or whatever name you gave it.

7.11 Wait while your computer installs MacOS. You’ll need to be connected to the internet. If not, you’ll get prompted to select a network and password if you don’t have a wired connection. This step will take about 45 minutes to one hour, even though it starts out saying something like 8 minutes.

Notes on 7.11:

  • If you did not erase the drive correctly, what happens is you’ll get to almost the end…and then you’ll get a message telling you that Mac OS cannot be installed. This is because the OS is still installed and it can’t be overwritten in this way.
  • I’ll also note that you cannot install an operating system your computer didn’t come with using these instructions. You cannot try to rollback to Mojave from Catalina, for instance, using this method.
  • These notes are written for Catalina (and other computers that have not had their operating systems upgraded). I do not know what happens to computers that have been upgraded. It’s possible reinstalling MacOS installs the OS originally installed on the computer, or it could be the last OS installed.

7.12 Computer restarts in welcome, setup mode. Once the operating system has been properly installed, the computer will automatically re/start in the welcoming start-up screens that you encounter on a brand new computer. Continue as necessary.

7.13 If you do not want to continue, press Command + Q to quit the start-up and the computer will shut down. If you have a laptop, it will power up automatically when the lid is opened.

Reinstall Catalina On Mac

Now you’re completely done! Hope that was helpful.

Extra resources:

  • Searching further, I found instructions from MacWorld that specifically references Catalina. How to wipe and factory-reset a Mac: the method has changed in Catalina. These instructions were thorough in some ways, but also not correct in others.
  • To gain more courage in this process, I watched this video from AppleInsider. It is NOT tailored for Catalina. But it was helpful from an overall process perspective. I’ve queued it to start at Disk Recovery.

Extra Tips:

  • Keep the computer plugged in to power.
  • Try not to let your computer go to sleep during Reinstall MacOS.
  • Use another computer to read instructions vs your phone. It’s easier to search and switch between windows, if you’re not using instructions that are all on one page.
  • Back up your data ahead of time, if you intend to keep the files.

Using My Own Instructions to Wipe an iMac Running Mojave

As mentioned, I’ve been on the hunt for a new computer for a few months. I’ve tried 3 different Macs — 2 laptops and an iMac, as the title states. The 2 laptops I bought from Apple’s refurbished store. The iMac was purchased from Other World Computing.

OWC conveyed that wiping the computer was not necessary, but I chose to do it anyway. I referenced my own list above. I only have a few tips to add.

How To Reinstall Catalina On Mac

  • Definitely check iMessage to sign out. I hadn’t opened it before, and assumed that I hadn’t been logged in. Turns out I still needed to sign out.
  • Confirm sign outs via iCloud. Use iCloud to confirm your account has been fully signed out from all computers/devices that you don’t want associated with your account.
  • Check that if any licenses or subscriptions need to be deactivated. For instance, I had purchased a second copy of CleanMy Mac when I had the laptops running Catalina. In order to use the license on another computer, it had to be deactivated via the CleanMyMac website. It doesn’t matter that the drive was wiped. In addition, not only could Catalina not run older Adobe software, it also couldn’t run the uninstallers.
  • Stick with the default drive format. I was also not exactly sure about the drive format. So I checked the Apple website again, and just stuck with the default choice: “Format: Choose APFS or Mac OS Extended (Journaled). Disk Utility shows a compatible format by default.”